<?php

/*
	Question2Answer (c) Gideon Greenspan

	http://www.question2answer.org/

	
	File: qa-include/qa-db-blobs.php
	Version: See define()s at top of qa-include/qa-base.php
	Description: Database-level access to blobs table for large chunks of data (e.g. images)


	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.
	
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	More about this license: http://www.question2answer.org/license.php
*/

if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
    header('Location: ../');
    exit;
}


function qa_db_blob_create($content, $format, $sourcefilename = null, $userid = null, $cookieid = null, $ip = null)
    /*
        Create a new blob in the database with $content and $format, other fields as provided
    */
{
    if (qa_to_override(__FUNCTION__)) {
        $args = func_get_args();
        return qa_call_override(__FUNCTION__, $args);
    }

    for ($attempt = 0; $attempt < 10; $attempt++) {
        $blobid = qa_db_random_bigint();

        if (qa_db_blob_exists($blobid))
            continue;

        qa_db_query_sub(
            'INSERT INTO ^blobs (blobid, format, content, filename, userid, cookieid, createip, created) VALUES (#, $, $, $, $, #, INET_ATON($), NOW())',
            $blobid, $format, $content, $sourcefilename, $userid, $cookieid, $ip
        );

        return $blobid;
    }

    return null;
}


function qa_db_blob_read($blobid)
    /*
        Get the information about blob $blobid from the database
    */
{
    if (qa_to_override(__FUNCTION__)) {
        $args = func_get_args();
        return qa_call_override(__FUNCTION__, $args);
    }

    return qa_db_read_one_assoc(qa_db_query_sub(
        'SELECT content, format, filename FROM ^blobs WHERE blobid=#',
        $blobid
    ), true);
}


function qa_db_blob_set_content($blobid, $content)
    /*
        Change the content of blob $blobid in the database to $content (can also be null)
    */
{
    qa_db_query_sub(
        'UPDATE ^blobs SET content=$ WHERE blobid=#',
        $content, $blobid
    );
}


function qa_db_blob_delete($blobid)
    /*
        Delete blob $blobid in the database
    */
{
    if (qa_to_override(__FUNCTION__)) {
        $args = func_get_args();
        return qa_call_override(__FUNCTION__, $args);
    }

    qa_db_query_sub(
        'DELETE FROM ^blobs WHERE blobid=#',
        $blobid
    );
}


function qa_db_blob_exists($blobid)
    /*
        Check if blob $blobid exists in the database
    */
{
    if (qa_to_override(__FUNCTION__)) {
        $args = func_get_args();
        return qa_call_override(__FUNCTION__, $args);
    }

    return qa_db_read_one_value(qa_db_query_sub(
        'SELECT COUNT(*) FROM ^blobs WHERE blobid=#',
        $blobid
    )) > 0;
}


/*
	Omit PHP closing tag to help avoid accidental output
*/